Page 286 - Trenchless Technology Piping Installation and Inspection

250 Cha pte r S i x

quality control and quality assurance measures usually specified for a
traditional open-cut projects, there are several measures specific to
pipe-bursting operations. These measures can take the form of tests,
certifications, inspection procedures, and the like. Extensive listing of
the relevant required submittals, careful preparation of the submittals,
and carefully review and approval of the submittal are significant
steps in the QA/QC program. The QA/QC program should state the
performance criteria for the product line and the acceptable tolerance
from these criteria. For example, the invert of the new pipe should not
deviate from the invert of the existing pipe by more than a specified
number of inches, the depth of sags in the new pipe should not exceed
one inch, and the difference in the vertical and horizontal dimensions
of the new pipe diameter (ovaling) should not exceed 2 percent.
The QC program should state how these performance criteria
will be measured, tested, and checked. Some of the methods for veri-
fying performance are post-bursting CCTV inspection, pressure test-
ing, and mandrel test. The surface and subsurface displacement-
monitoring program should be outlined in the specifications along
with the acceptable amount of ground movement. Certifications from
the manufacturers of the bursting system, replacement pipe, and
other materials may be required to verify that these products meet
the contract specifications, based on tests conducted by the manufac-
turer or a third party. For challenging projects, the presence of the
bursting system manufacturer representative at the jobsite may be
required. The owner’s quality assurance program should ensure that
the field and management team of the contractor have the knowledge
and the experience needed to complete the project successfully and
are able to respond appropriately to unforeseen problems.
It is critical that the contractor ensure that the replacement pipe
meets the specifications before, during, and after bursting. Adhering
to the quality control and quality assurance plans during the manu-
facturing and shipping to the site, along with proper unloading of the
pipe, reduces risk of pipe damage. Pipe fusion operations should be
performed by well-trained (preferably certified) workers under
appropriate supervision to reduce the risk of future pipe problems
when repair would be difficult and costly. For pressure applications,
the new pipe should be inspected and pressure tested prior to burst-
ing, as well as after completion of the installation.
6.8.11 Dispute Resolution Mechanisms
As for any trenchless methods, the contract should include clauses
addressing the possibility of different site conditions and unforeseen
conditions that allow contract time and amount adjustment if the
conditions at site materially differ from the conditions expected and
indicated in the bid documents. See Chap. 9 for more information on
geotechnical baseline reports (GBR) and other dispute resolution
mechanisms.